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Hello, Is this a Hesperosaurus mjiosi fossil? It was collected in Bone Cabin quarry Wyoming and measures 8 x 8.5 inches. Thanks

These finds were reported a while back and this paper describes the finds. These two partial skeletons from Montana represent the northernmost occurrences of Stegosauria within North America ever recovered from the Morrison Formation http://app.pan.pl/article/item/app005852018.html

While doing research on dino stratigraphy in the Morrison Formation, I noted that Hesperosaurus has been found at the bottom of the Morrison Formation and also the Salt Wash Member near Howe Quarry (where a specimen of Stegosaurus armatus has been found), roughly the same level as the plethora of Stegosaurus specimens found at Como Bluff Quarry 13. At the same time, I've noticed that the primitive apatosaurine Eobrontosaurus has been found to coexist with the advanced diplodocine Diplodocus in Garden Park, Colorado. Since the most primitive Morrison dinos (Eobrontosaurus, Hesperosaurus, "Allosaurus jimmadseni") are found in the lower part of the Salt Wash Member and coexist with the their more advanced counterparts at the Howe Quarry (which is situated near the boundary between the Salt Wash and Brushy Basin Members), would it be reasonable to assume that the rate of faunal turnover for dinosaurs in the Morrison Formation was a gradual one, with Hesperosaurus and Eobrontosaurus being eventually replaced by Diplodocus and Stegosaurus in the Brushy Basin Member?